Here are two ways to make a gauge (speedometer); one uses the Canvas another uses GoogleCharts Make an Analog Gauge and use it to display something useful. The example shows an Altimeter gauge; you can instead plot km/hr or miles/hr by adapting the Blocks.
Here is how the LocationSensor measures speed https://groups.google.com/g/mitappinventortest/c/OxxRsUWzwpw/m/-JlxAS49AwAJ .
Try some Blocks, if you still have issues ask again and you will get specific advice.
Some time ago I wrote an app as you describe using the Canvas. I will see if I can find the code.
